Apparatus for hydrocarbon determination



Dec. 22, 1953 R. L. DOAN 2,663,379

APPARATUS FOR HYDROCARBON DETERMINATION Filed May 10, 1948 4 BRIDGE AMPLIFIER 7 2' RECORDER 4B T WIRE ANALYZER BU TANE AIR MIXTURE DRILLING MUD INVENTOR. RICHARD L. DOAN A T TORNEVS TO SHALE SHAKER OR PIT Patented Dec. 22,1953

APPARATUS FOR HYDROCARBON DETERMINATION Richard tiayinoat, Bartlesvil le, Okla., assignor t'iifliillips' Ptliileiim company, a cii'fpoiatibh of Delaware Application May 10, 1948, Serial No.-26;118

This invention relates to apparatus for de termining relative hydrocarbon contents of. drilling muds continuously or intermittently during drilling operations.

Heretofore, many different types of apparatus have been devised for analyzing the hydrocarbon content of drilling muds. In some cases, ap aratus is provided for extracting substantially all of the gas from a smallvolume of mud by the use of heat and. suction while, in other instances, a partial extraction is made on a by-pass fraction of the main mud stream by the use of suction alone. Although such apparatus may yield valuable and accurate results, it requires bulky and expensive equipment. Hence, it is not suitable for use on wells where it is uneconomical to employ a field laboratory unit requiring several operators.

It is an object of this invention to provide a simple and inexpensive apparatus for determining the hydrocarbon content of drilling muds.

It is a further object ofthe invention to provide apparatus which maybe used for long periods of time without requiring the attention of an operator.

It is a still further object of the invention to provide apparatus for hydrocarbon ;determination which is reliable in operation, utilizes few components, and is of rugged construction, capable of withstanding much abuse in the field.

Various other objects, advantages andfeatures of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing, in which the figure is a schematic flow diagram of the apparatus of this invention. 3

Referring now to the drawing in detail, I have shown a line II] for conveying drilling mud from a Well to a surface portion of the mud circulating system. A branch conduit llv extends vertically upward from line I!) at a suitablelocation and a valve [2 is interposed in the line It at the downstream side of the conduit ll. It will be apparent that a portion of the mud from line It flows through valve. l2 directly into the circulating system while the rest of the mud is bypassed and escapesthrough conduit ll, the-proportion of mud passing through conduit being controlled by the valve I2, H 4

As the mud emerges from the outlet of conduit I I, it flows along a downwardly inclined surface I3 of a generally frusto conical flange member M which is securedto the upper end of the conduit; In thisma-nner, the mud stream'flowing from the conduit is spread out over the down- 3 claims. (01. its-2J5) 2 wardly sloping surface l3, thereby ereatinga condition favorable to the maximum release of the hydrocarbon and other gases contained therein. From the flange member I4, the mud flows into a container l5 which has a downwardly inclined surface 16 leading to a shale shaker, mud pit, or other part of the surface circulatory system. Mounted above the conduit H and frustoconical member I4 is a hood 1-8 which comprises an upper frusto-conical section l9 and a lower cylindrical section 20, the lower end of the section 20 being closely spaced to the peripheral portions of the member I l, The spacing between these parts is so adjusted that there is a small clearance between the cylindrical section 20 and the surface of the mud stream flowing over the inclined surface I3. 'As a result, air isdrawn into the hood along with the hydrocarbongases from the mud by the suction system to be hereinafter described. In practice, the diameter of the hood may be about ;1 to 3 feet depending on the size of the conduit II and its surrounding flanged member l4. 1

From the hood it}, the mixed air and hydro carbon gases flow through a condenser unit 23 which has a coil 22 positioned therein and conneeted to an inlet 24 and an outlet 25 so that cold water or other cooling fluid may be circulated through coil In this condenser, water vapor contained in the hydrocarbon gas-air mixture is condensed and drops back through the hood l8 into the container 15. The cooled gases flow from the condenser unit 23 through a'valve 1 21 to a conduit 28 which leads to a drier unit 23.

The dried gases then pass through a conduit 30, Which includes a Variable choke 3|, to a hot Wire analyzer unit 32. From the analyzer, the gases flow through a metering device, such as a lfiibble gaugesa, 'a line 34, an adjustable valve 35 for controlling the volume rate of flow of the gas, and a solenoid controlled valve '36 to a vacuum pump or aspirator 31. The line 31 and conduit 28 are interconnected'by a la -pass line-4g'jwhich includes a variabl'e'chokefil an'da Valve.

When the aspirator 31 is operated, it will be apparent that the mixed air and hydrocarbon gases from the hood I8 are drawn through cohdenser 23 and valve 21 into the conduit 28', from which a portion of the gases flows through drier 29, choke 3|, analyzer 32, and bubble gauge '33 to line 34 while the remainder of the gases flows through Valve 42, choke ll, and conduit 4,0 to line 34. The proportion of gases flowing in these two branches may be regulated bya'dju stnient of the chokes 3|, 4|. to the end that the minimum quantity of gas necessary for analysis is passed through the drier and analyzer 32, thereby conserving the calcium chloride or other drying agent in the unit 29. Alternatively, the fiow of gas through the system may be obtained by mounting a small blower at the top of condenser 23 with the suction end toward the condenser so that the gas mixture is drawn from the condenser by the blower and then forced through the rest of the system by the pressure of the blower.

The analyzer 32 contains a hot wire unit which is connected by leads to a unit 45, the hot wire forming one arm of a Wheatstone bridge gas detector, as described in U. S. Patent 2,349,250. The method of measuring the concentration of combustible gas in the analyzer is essentially the same as described in said patent except that an amplifier 41 and a recorder unit 48 are substi M tuted for the indicating microammeter represented by reference character I5 in Figure 1 of said patent. The recorder 48 may include a clock driven chart, which may move at the rate of about 2 to 6 inches per hour, and suitable devices may be provided to mark actual time intervals at the edge of the chart and also to register progress of the drill bit upon the chart as a function of time.

Another type of chart drive ofiering some advantages over the conventional clock drive is one in which the chart is driven by the mud pump. Each stroke of the mud pump sends a known volume of mud down the hole, and the circulation time may be conveniently determined by counting the number of strokes of the mud pump required to send a tracer material, such as oats, from the surface to the bottom of the hole and back to the surface. By mounting an appropriate switching device on the mud pump so that it it actuated once for each stroke of the pump, and then using this in conjunction with an electromagnetic device which drives the chart through a suitable gear system, it is possible to advance the chart by any desired amount for each stroke of the pump. For example, the gearing might be arranged so that each horizontal line on the chart represents one thousand strokes of the mud pump. Then if the circulation time from the bottom of the hole for a given depth is 4500 strokes it is a simple matter to check back that amount on the drilling progress chart to determine the depth of origin of any excess gas which has been registered for mud arriving at the surface. terms of elapsed time on a clock-driven chart if the pump is operated continuously during the interval. But if the pump is stopped for a few minutes this would have to be taken into consideration on the clock-driven chart whereas it would not on a chart driven by pump strokes.

I also provide means for admitting a gas sample of known composition to the analyzer 32 so that the recorder may be suitably calibrated to indicate the combustibility of unknown hydrocarbon mixtures. To this end, a container 4'9 is connected to conduit 28 through a valve 50 and it will be apparent that the gas, such as a butaneair mixture, in container 49 may be fed through the system for the purpose of calibrating the bridge and recorder apparatus. A valve 5! is also provided for admitting air to conduit 28 for calibration purposes or to purge the system of hydrocarbon gases.

After the analyzer is calibrated, the apparatus The same thing could be done in 1 is in condition to measure the relative hydrocarbon content of the gases escaping from the drilling mud. Preferably and advantageously, the analyzer is operated at predetermined intervals of about one to five minutes, each measurement requiring a period of approximately five seconds. I also prefer that the flow of gas through the analyzer be stopped while the measurement is being made. Thus, the gas is substantially quiescent during the analysis thereof so that a very sensitive bridge may be utilized due to the absence of convection currents in the analyzer. To this end, I may provide a timer 52 which consists of a clock driven insulating disc having suitable conductive metal strips therein cooperating with fixed contact points, one set of contacts being connected through leads 53 to solenoid operated valve 36 and another set of contacts being connected by leads 54 to the bridge unit 46. Alternatively, the timer 52 may include a set of clock-driven discs having bosses which actuate independent switches by mechanical contact.

The timer is energized at predetermined intervals of five minutes, for example, and at each energization thereof, a circuit is made through leads 53' to close valve 36 and stop circulation of gas through the system. A few seconds later, the bridge 46 is energized through leads 54 and the hydrocarbon content of the gas in analyzer 3'2 is recorded on the chart of unit 48. When the analysis is completed, the circuits through leads 53, 54 are opened by the timer with the result that the bridge unit 56 is de-energized and valve 36 is opened to reestablish circulation of gas through the system.

Accordingly, an indication of the hydrocarbon content of the gas escaping from the drilling mud is made on the chart at periodic intervals and these indications may be compared with one another to determine the variations in the amount of combustible gas released from time to time as the drilling progresses. Any relative increase in the indicated combustible gases is interpreted as an increase in the load of gas carried by the mud reaching the surface at the time indicated on the chart. This excess gas was picked up by the mud as it traversed the drill bit at the bottom of the hole during the drilling of a gasbearing formation. To determine the depth at which the bit was drilling at the time the excess gas entered the mud, use is made of the drilling progress chart previously mentioned, with a correction for the time required for the mud to get from the bottom of the hole to the surface. The circulation time can be determined as frequently as desired by any one of several wellknown methods.

It will be apparent that I have provided means for collecting and measuring the combustible gas which escapes from'the mud as it emerges into the atmosphere. The apparatus does not, of course, record the total gas content of the mud since a considerable amount of gas is retained in the mud by adsorption and entrainment. However, variations in the hydrocarbon content of the gas escaping from the mud are a useful index of the actual hydrocarbon content of the mud itself and this index yields valuable information as to the nature of subterranean formation traversed by the drill bit. It will also be apparent that I have provided apparatus for recording the hydrocarbon content of the mud at predetermined intervals without requiring the supervision of an operator so that the present apparatus may be advantageously utilized on wells where it is uneconomical to employ a field laboratory unit requiring several Operators. However, I do not wish to limit myself to intermittent measurement as it will be apparent that the hydrocarbon content may be continuously determined by eliminating the timer 52 and valve 36 so that a continuous stream of gas flows through the apparatus.

While the invention has been described in connection with a present, preferred embodiment thereof, itis to be understood that this description is illustrative only and is not intended to limit the invention, the scope of which is defined by the appended claims.

Having described my invention, I claim: 7

1. Improved drilling mud gaseous extraction apparatus comprising, in combination, a drilling mud conduit having an upright positioned branch thereof, a member having a downwardly inclined surface disposed at the outlet of said branch conduit for spreading out the mud discharged therefrom, a hood for trapping gases escaping from the mud having its lower end closely spaced to the edge portions of said surface defining an opening between said hood and said surface through which the interior of said hood is in direct communication with the atmosphere surrounding said hood whereby atmospheric air can enter said hood through the opening between said hood and said surface, and means for withdrawing the resulting gases from said hood.

2. Improved drilling mud gaseous extraction apparatus comprising, in combination, a drilling mud conduit having an upright end portion, a member having a downwardly inclined frustoconical surface disposed at the outlet of said conduit for spreading out the mud discharged therefrom, a hood for trapping gases escaping from the mud having its lower end closely spaced to the edge portions of said surface defining an opening between said hood and said surface through which the interior of said hood is in direct communication with the atmosphere sur rounding said hood whereby atmospheric air can 6 enter said hood through the opening between said hood and said surface, and means for withdrawing the resulting gases from said hood.

3. Apparatus to extract gases from drilling mud comprising, in combination, a drilling mud conduit having an upright positioned branch thereof, a valve disposed in said conduit downstream from said branch to regulate the flow of mud through said branch, an annular frusto-conical terminal flange connected to the upper end of said branch whereby the mud flows upwardly through said branch and outwardly and downwardly over said flange, and a conical hood having a depending annular sleeve spaced from said flange to form an annular space therebetween through which the interior of said hood has direct communication with the surrounding atmosphere, through which the drilling mud passes outwardly and through which atmospheric air passes inwardly over the drilling mud.

RICHARD LLOYD DOAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 457,917 Shaw Aug. 18, 1891 1,095,463 Kieser May 5, 1914 1,707,624 Brown Apr. 2, 1929 2,126,596 Wood Aug. 9, 1938 2,185,394 Arbogast Jan. 2, 1940 2,281,962 Van Tongeren May 5, 1942 2,341,169 Wilson et al. Feb. 8, 1944 2,370,817 Shanley Mar. 6, 1945 2,400,046 Hummel May 7, 1946 2,408,964 Winn et a1 Oct. 8, 1946 2,484,202 Wintermute Oct. 11, 1949 2,489,180 Hayward Nov. 22, 1949 FOREIGN PATENTS Number Country Date 377,895 Great Britain Aug. 4, 1932 573,759 Germany Apr. 5, 1933 

